Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Feel free to suggest a word for inclusion in this Glossary. We will do our best to post a helpful answer.
A
Analogue
Representing something in the real world. Analogue is often used in comparison with Digital, for example comparing analogue and digital computers or analog or digital electrical signals. Analogue computers actually measure, analyze and compute using real physical measures and numbers. Analogue electrical signals (such as the radio frequencies used to transmit telecommunications information) are directly generated by physical stimuli in the form of light or sound waves.
B
Backbone
A segment of a network that's often a higher speed than the rest of the network and connects all the other segments. If you don't have a fast backbone, your network will lag. That's why a lot of ISPs are constantly restructuring their backbones.
Bandwidth
This is a measure, in some amount of bits per second, of the amount of data that can be sent over a particular cable, interface, or bus.
Broadcasting
A radiocommunication service in which signals transmitted or retransmitted by space stations are intended for direct reception by the general public. In the broadcasting-satellite service, the term "direct reception" shall encompass both individual reception and community reception.
C
D
Digital
The conversion of information into a binary format (1's and 0's or on's and off's), the smallest or simplest unit of information being a bit. These bits of information may be transmitted using radio frequency techniques such as terrestrial broadcasting, satellite and microwave transmission or over coaxial or fiber optic cable and copper wire. Digital information may be manipulated at extremely high speeds.
Downstream
This refers to the downloading (receiving) of data from the Internet to a client machine. Downstream speeds are typically greater than upstream speeds in high speed consumer Internet connections such as cable modems and ADSL.
Duplex
This term is a telecommunications term that describes part of the communications between a local modem and a remote computer. In full duplex mode, the remote computer is set up to return the characters that are sent to it so that they can be displayed on your screen. In half duplex mode, the remote computer does not return the characters sent to it. Also see full duplex and half duplex for descriptions of the those terms in other contexts.
DVB (Digital Video Broadcasting)
It is a consortium of around 300 companies in the fields of Broadcasting, Manufacturing, Network Operation and Regulatory matters that have come together to establish common international standards for the move from analogue to digital broadcasting. This common market-led initiative has resulted in DVB becoming a prominent and leading international standard and the sole choice for technologies that enable an efficient, cost effective, easy/rapid transition, higher quality and interoperable digital broadcasting. We have established the DVB logo as an instant and recognizable representation of the DVB brand and its values. The DVB Project Office and its 3.5 staff are based in Geneva, Switzerland. It is the nucleus of the Administration and MarComms of the Consortium.
DVB card
It is a card that is able to receive data broadcasting (e.g., the download of software, Internet services) over satellite network. The card should have these features : fully compliant with MPEG-2 based DVB transmission standards, fully universal compatible Tuner 900-2150 MHz, QPSK Demodulator, Extended symbol rate (2-45 MS/s), MCPC/SCPC capable, support for DiSEqC* 1.0 LNB control, fully compliant with DVB data broadcasting specification (ETSI EN 301 192), Support of IP unicasting and multicasting. It can also be an external device like a box.
E
Encoder
A device that converts an analog signal to a digital signal that represents equivalent information. Synonyms analog-to-digital
Extranet
An Extranet is an intranet that extends onto the Internet. Confusing? Yes. Extranets are external extensions of a company's intranet that allow certain people to interact from the Internet. Not all intranets are Extranets.
F
FTP
File Transfer Protocol. A higher level protocol, used in conjunction with TCP/IP.
G
Gateway
A device that connects two different types of network together.
H
I
Intranet
Local network of computers using TCP/IP as the standard communications protocol. Usually an Intranet features some sort of HTML content that you can use a browser to look at. Think of it as a mini, private Internet.
IP Address
The specific network address of a computer on a network using TCP/IP as its network protocol.
Internet Service Provider (ISP)
An ISP provides Internet access to people or corporations. ISPs generally have pools of modems awaiting dial-up connections. Smaller ISPs buy bandwidth from larger ISPs.
J
K
L
M
Modem (MOdulator, DEModulator)
A device that you connect to your computer and to a phone line, that allows the computer to talk to other computers through the phone system. Basically, modems do for computers what a telephone does for humans.
MPEG-2 & MPEG-4
MPEG is the designator that identifies an international standard for compression of TV signals, which standard is used in conjunction with desktop computers for video presentations or clips. MPEG-2 and 4 are audio / visual compression standard designed by Moving Pictures Experts Group for devices that can read or write about 4 Mbits/second worth of data. MPEG-4 uses a higher compression rate then MPEG-2.
Multicast (sending a single file to many users)
Is similar to broadcast. Multicast data, once requested by one person, can be received by any number of people. Multicasting is therefore a very efficient way of sending data from a single server to millions of simultaneous users. Once the data stream is being broadcast, any other user can choose to select the same stream after receiving the necessary parameters from the originating server. This allows service providers the choice of providing the content freely, on a subscription basis or via pay-per-view. Content providers can therefore "push" their content over satellite for reception. This solution is ideal for Web broadcasting of, say, weather, news, financial information and sports, as well as for audio/video streaming and customised services. No return link is required.
Multimedia
This refers to any use of audio or video in a computer. In simplest terms, this refers to the basic functions of sound cards and video cards. In addition the term also covers television and video integration in computers.
Multiplexer (Mux)
This is technically a logic circuit that sends one of several inputs out over a single output channel. In the network world, it is used to describe devices that send several signals over a single line at the same time. The device on the other side of the wire that receives the signal is a demultiplexer.
N
O
P
Packet
A collection of information. It is often used to refer to the pieces of information sent over computer networks.
Proxy
This is the use of one computer or device to make requests in place of another over a network. Proxies are often used for Internet security or control of connections. You can use a proxy or proxy server to pass data between your internal network and the Internet. A machine on your network sends a request to the proxy. The proxy sends the request to a server on the Internet. Thus, it stands in for the computer on your network. The server on the Internet never knows that the request is coming from anywhere but the proxy. Thus 100 machines on your network could all access an Internet server and it would look like the proxy was making all of the requests. Some proxies have caching and site filtering built in.
Pull
The user accesses the multimedia content (Pull mode) by submitting information requests from a modem connected to a telephone or ISDN line via either a local ISP or the multimedia service operator. The data is retrieved by satellite. Typical applications: Web site visits, Best of the Web, software downloading, on-line newspapers, interactive multimedia, etc.
Push Technology
In electronic marketing, to send data to another computer without a direct request from (via) that computer.
Q
R
Router
A device that bridges an internal network to another network. Take a ferry as an example: cars that need to go to the other side of a body of water (another network) need to use the ferry (the router). If they want to stay on their side, they simply don't go on the ferry. Also a device used to bridge a computer to a long distance digital communications network, such as ISDN.
S
Streaming
A technique for transferring data (usually over the Internet ) in a continuous flow to allow large multimedia files to be viewed before the entire file has been downloaded to a client's computer.
T
TCP/IP (Transmission Control Protocol/Internet Protocol)
This is the suite of protocols that defines the Internet. Originally designed for the UNIX operating system, TCP/IP software is now available for every major kind of computer operating system.
Transponder
A combination receiving and transmitting antenna on a communications satellite. A frequency converter is also including in the transmit/receive package which converts the uplinked signal frequency to a transmission or downlink frequency.
U
V
VSAT (Very Small Aperture Terminal)
Earth station satellite antenna with a diameter or cross-section dimension in the general range of 1.2 to 2.4 meters.
W
X
Y
Z
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